U.S. patent application number 11/494542 was filed with the patent office on 2007-02-01 for power transmission chain and power transmission device.
This patent application is currently assigned to JTEKT Corporation. Invention is credited to Yoshihisa Miura.
Application Number | 20070026987 11/494542 |
Document ID | / |
Family ID | 37307199 |
Filed Date | 2007-02-01 |
United States Patent
Application |
20070026987 |
Kind Code |
A1 |
Miura; Yoshihisa |
February 1, 2007 |
Power transmission chain and power transmission device
Abstract
A power transmission chain includes a plurality of links, a
plurality of pins, and a plurality of interpieces. Each of the
plurality of links is formed of a link with a column of which
stretch is suppressed by having front and back insertion parts made
to be respectively independent through holes, and a link without a
column which is relatively stretched easily by connecting front and
back insertion parts into one through hole. The links with columns
and the links without columns are mixed based on a certain mixture
pattern.
Inventors: |
Miura; Yoshihisa;
(Kooriyama-shi, JP) |
Correspondence
Address: |
C. IRVIN MCCLELLAND;OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
JTEKT Corporation
Osaka-shi
JP
|
Family ID: |
37307199 |
Appl. No.: |
11/494542 |
Filed: |
July 28, 2006 |
Current U.S.
Class: |
474/206 |
Current CPC
Class: |
B21L 15/005 20130101;
F16G 13/04 20130101; F16G 13/06 20130101; F16G 5/18 20130101 |
Class at
Publication: |
474/206 |
International
Class: |
F16G 13/02 20060101
F16G013/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 29, 2005 |
JP |
2005-221420 |
Claims
1. A power transmission chain comprising: a plurality of links
having front and back insertion parts through which pins are
inserted; and a plurality of first pins and a plurality of second
pins aligned back and forth, for connecting the links aligned in a
chain width direction so that a front insertion part of one link
corresponds to a back insertion part of another link; wherein the
first pins and the second pins move relatively in a rolling and
contacting manner so as to enable bending in a longitudinal
direction of the links, each of the plurality of links is formed of
a link with a column of which stretch is suppressed by having the
front and back insertion parts as respectively independent through
holes, and a link without a column which is relatively easily
stretched by connecting the front and back insertion parts into one
through hole; and the links with columns and the links without
columns are mixed based on a certain mixture pattern.
2. The power transmission chain according to claim 1, wherein, in
the mixture pattern, all the links corresponding to the width
direction are either the links with columns or the links without
columns.
3. The power transmission chain according to claim 1, wherein, in
the mixture pattern, the links located at a most outside in the
width direction of each row are the links without columns and the
remaining links are the links with columns.
4. The power transmission chain according to claim 1, wherein one
of the first pin and the second pin is fixed to the front insertion
part of one link and is movably fitted in the back insertion part
of the other link; and the other one of the first pin and the
second pin is movably fitted in the front insertion part of the one
link and is fixed to the back insertion part of the other link.
5. A power transmission device comprising: a first pulley having a
conical sheave face, a second pulley having a conical sheave face,
and a power transmission chain provided over the first and second
pulleys; wherein the power transmission chain is the power
transmission chain according to any one of claims 1 to 4.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a power transmission chain,
and more particularly, to a power transmission chain preferable for
a continuously variable transmission (CVT) of an automobile or the
like and a power transmission device using the power transmission
chain.
[0002] As shown in FIG. 7, as a continuously variable transmission
for an automobile, there has been known one which includes: a drive
pulley (2) having a fixed sheave (2a) and a movable sheave (2b),
which is provided on an engine side; a driven pulley (3) having a
fixed sheave (3b) and a movable sheave (3a), which is provided on a
drive wheel side; and an endless power transmission chain (1) which
is provided over the both, in which the movable sheaves (2b) and
(3a) are caused to come close to or leave away from the fixed
sheaves (2a) and (3b) by a hydraulic actuator, whereby a chain (1)
is cramped by a hydraulic pressure so as to cause a contact load
between the pulleys (2) and (3) and the chain (1), and torque is
transmitted by a frictional force of the contact part.
[0003] As the power transmission chain, Publication of Japanese
Patent Application Laid-open No. H08-312725 proposes one which
includes: a plurality of links having front and back insertion
parts through which pins are inserted; and a plurality of first
pins and a plurality of second pins for connecting the links
aligned in a chain width direction so as to be bendable in a
longitudinal direction such that a front insertion part of one link
and a back insertion part of another link correspond to each other,
in which a first pin fixed to a front insertion part of one link
and movably fitted in a back insertion part of another link and a
second pin movably fitted in the front insertion part of the one
link and fixed to the back insertion part of the other link move
relatively in a rolling and contacting manner so as to enable
bending in the longitudinal direction between the links.
[0004] The power transmission chain according to Publication of
Japanese Patent Application Laid-open No. H08-312725 has been
required to be further downsized and be further decreased in
weight. However, there is generally a tendency such that a
durability of a link is lowered if the power transmission chain is
downsized or decreased in weight. A main cause of the link damage
is a fatigue cut damage due to the fact that the chain continuously
receives a stress. Therefore, as a counter measure against this, it
is considerable that the link is formed in a shape such that the
link is easily transformed (easily stretched) so as to suppress a
stress generated in the link. However, if the stretch of the link
becomes larger, the entire length of the chain is made longer so
that there is a possibility that a transmission performance and a
driving performance necessary for the chain cannot be
maintained.
SUMMARY OF THE INVENTION
[0005] An object of the present invention is to provide a power
transmission chain and a power transmission device which can relax
concentration of stresses generated in the link and suppress
stretch of the chain at the appropriate value.
[0006] A power transmission chain according to the present
invention includes a plurality of links having front and back
insertion parts through which pins are inserted; and a plurality of
first pins and a plurality of second pins aligned back and forth,
for connecting the links aligned in a chain width direction so that
a front insertion part of one link corresponds to a back insertion
part of another link; wherein the first pins and the second pins
move relatively in a rolling and contacting manner so as to enable
bending in a longitudinal direction of the links, each of the
plurality of links is formed of a link with a column of which
stretch is suppressed by having the front and back insertion parts
as respectively independent through holes, and a link without a
column which is relatively easily stretched by connecting the front
and back insertion parts into one through hole; and the links with
columns and the links without columns are mixed based on a certain
mixture pattern.
[0007] In the link with a column, independent front and back
through holes are formed in the link, and the front through hole is
made into a front insertion part and the back through hole is made
into a back insertion part. In the link without a column, one
through hole which is longer back and forth is formed in the link
and the front part of the through hole is made into a front
insertion part and the rear part of it is made into a back
insertion part, respectively.
[0008] Each number of the link with a column and the link without a
column can be freely set. The mixture pattern can be obtained, for
example, by replacing the link with a column located at the place
where concentration of stress easily occurs (the opposite end
portions in the width direction or the part having the less number
of links per row or the like) with the link without a column under
the condition that stretch of the chain is kept appropriately based
on the case that all of the links have the columns.
[0009] Any one of the first pin and the second pin may be pressed
and fixed in the front and back insertion parts of the link or the
both of them may not be fixed (they are movably fixed). In
addition, the first pin and the second pin have the different
sectional shapes or they may have the same shapes. Further, the
first pin and the second pin may be formed in the same lengths and
the both of them may contact the sheave faces, or they may be
formed in the different lengths and only the longer one may contact
the sheave face.
[0010] At least one of the first pin and the second pin may
transmit a power by a frictional force contacting the pulley. In
the chain where any one of the pins contacts the pulley, any one of
the first pin and the second pin is defined as a pin to contact the
pulley when this chain is used by a continuously variable
transmission (hereinafter, referred to as "a pin"), and the other
one is defined as a pin not to contact the pulley (referred to as
an interpiece or a strip, hereinafter, referred to as "an
interpiece").
[0011] In the first pin and the second pin, for example, one
contact surface is flat, and the other contact surface is formed
into a desired curved face so that the pin can move in a rolling
and contacting relatively. In addition, in the first pin and the
second pin, each contact surfaces may be formed in a desired curved
face. In any case, forming the shape of the contact surface of each
pin of two kinds, respectively (for example, the shape having a
relatively large curvature and the shape having a relatively small
curvature), two kinds of sets of pins may be provided having the
different loci of the rolling-contact movement. For example, the
locus of a contact position of the first pin and the second pin is
an involute of a circle.
[0012] Further, in this specification, one end side in the
longitudinal direction of the link is defined as a front part and
the other end side is defined as a back part; however, this does
not mean that the longitudinal direction always coincides with the
front and back directions.
[0013] For example, the link is made of a spring steel and a carbon
tool steel; however, the material of the link is not limited to the
spring steel and the carbon tool steel but it is obvious that the
link is made of other steels such as a bearing steel. As a material
of the pin, appropriate steel such as bearing steel is used.
[0014] The pin is fixed to the front and back insertion parts in
such a manner that the inner margin of the insertion part is fitted
to the outer circumferential face, for example, by mechanical
pressing; however, in place of this, interference shrink fit or
cooling fit may be available. The first pin and the second pin are
fitted in one insertion part so as to face each other in the
longitudinal direction of the chain, and any one of them is fitted
and fixed on the circumferential face of the insertion part of the
link. This fixing by fitting is preferably carried out at the edges
(the upper and lower edges) being at right angles each other with
respect to the longitudinal direction of the insertion part. Thus,
in the chain to fix the pin by fitting, since the stress of the
fixing part is increased, an advantage of relaxation of
concentration of stresses due to usage of the link without a column
becomes particularly remarkable.
[0015] In the mixture pattern, for example, all the links
corresponding to the width direction are either the links with
columns or the links without columns. In this case, in the chain
having the different number of links aligned in a row in the width
direction, by making the row having more links of links without
columns and making the row having less links of links with columns,
it is possible to easily balance suppress of stretch and relaxation
of concentration of stresses. Alternatively, in the mixture
pattern, the links located at a most outside in the width direction
of each row are the links without columns and the remaining links
are the links with columns.
[0016] For example, this power transmission chain is manufactured
by holding the necessary number of pins and interpieces
perpendicularly on a table and then, pressing the links one by one
or in several pieces. Then, by pressing the appropriate number of
the link with a column and the link without a column one after the
other in the case of pressing the pin and the interpiece in the
link, each link can be arranged based on a certain mixture
pattern.
[0017] It is preferable that the power transmission chain described
above be one in which one pin (interpiece) is to be shorter than
the other pin (pin), and end faces of the longer pin contact
conical sheave faces of a pulley of the continuously variable
transmission, and power is transmitted by a frictional force caused
by this contact. Each pulley is made by a fixing sheave having a
conical sheave face and a movable sheave having a conical sheave
face facing the sheave face of the fixing sheave, and a chain is
interposed between the sheave faces of the both sheaves, and the
movable sheave is moved by a hydraulic actuator whereby a winding
radius of the chain changes depending on the distance between the
sheave faces of the continuously variable transmission, which
enables variable transmission continuously with smooth
movement.
[0018] A power transmission device according to the present
invention includes a first pulley having a conical sheave face, a
second pulley having a conical sheave face, and a power
transmission chain provided over the first and second pulleys;
wherein the power transmission chain is any of the power
transmission chain as described above.
[0019] The power transmission device becomes one preferable to be
used as a continuously variable transmission of an automobile or
the like.
[0020] According to the power transmission chain and the power
transmission device, since the links with columns and the links
without columns are mixed, concentration of stresses is more
relaxed as compared to the case that all of the links have the
columns because the link without a column is easily stretched. In
addition, since stretch of the entire length of the chain is more
suppressed as compared to the case that all links have no column,
it is possible to prevent a transmission performance and a driving
performance necessary for the chain from being reduced. Thus,
without changing the outline shapes of the link and without
deteriorating other performances, the durability of the link can be
improved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a plan view showing apart of a power transmission
chain according to a first embodiment of the present invention;
[0022] FIG. 2 is an enlarged perspective view of the same;
[0023] FIG. 3 is an enlarged side view of a link with a column;
[0024] FIG. 4 is an enlarged side view of a link without a
column;
[0025] FIG. 5 is a plan view showing apart of a power transmission
chain according to a second embodiment of the present
invention;
[0026] FIG. 6 is a front view showing a state that the power
transmission chain is disposed to a pulley; and
[0027] FIG. 7 is a perspective view showing one example of a
continuously variable transmission in which the power transmission
chain according to the present invention is used.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] With reference to the drawings, embodiments of the present
invention will be described below. In the following description, up
and down refer to up and down in FIG. 3.
[0029] FIG. 1 and FIG. 2 show a part of a power transmission chain
according to the present invention. A power transmission chain (1)
includes a plurality of links (11) and (21) having front and back
insertion parts (12), (13), (22), and (23) which are disposed at
certain intervals in a longitudinal direction of the chain; and a
plurality of pins (first pins) (14) and interpieces (second pins)
(15) for connecting the links (11) and (21) aligned in a chain
width direction so as to be bendable in a longitudinal
direction.
[0030] For the links (11) and (21), two types, namely, the link
with a column (11) having the front and back insertion parts (12)
and (13) which are independent through holes, respectively; and the
link without a column (21) connecting the front and back insertion
parts (12) and (13) by a continuous part (24) so as to form one
through hole are used, and these link with a column (11) and link
without a column (21) are mixed based on a certain mixture
pattern.
[0031] As shown in FIG. 3, the front insertion part (12) of the
link with a column (11) is formed by a pin fixing part (12a) on
which the pin (14) (shown by a solid line) is fixed and an
interpiece movable part (12b) to which the interpiece (15) (shown
by a dashed-two dotted line) is movably fitted; and the back
insertion part (13) is formed by a pin movable part (13a) to which
the pin (14) (shown by a dashed-two dotted line) is movably fitted
and an interpiece fixing part (13b) on which an interpiece (15)
(shown by a solid line) is fixed.
[0032] In the same way, as shown in FIG. 4, the front insertion
(22) of the link without a column (21) is formed by a pin fixing
part (22a) on which the pin (14) (shown by a solid line) is fixed
and an interpiece movable part (22b) to which the interpiece (15)
(shown by a dashed-two dotted line) is movably fitted; and the back
insertion part (23) is formed by a pin movable part (23a) to which
the pin (14) (shown by a dashed-two dotted line) is movably fitted
and an interpiece fixing part (23b) on which the interpiece (15)
(shown by a solid line) is fixed. The front insertion (22) and the
back insertion part (23) of the link without a column (21) are
formed in the same shapes as the front insertion part (12) and the
back insertion part (13) of the link with a column (11).
[0033] As a result, the link with a column (11) and the link
without a column (21) are only different in with or without of the
continuous part (24) and their outline shapes and the shapes of
respective insertion parts (12), (13), (22), and (23) are the same.
Depending on with or without of the continuous part (24), the
stretch of the link with a column (11) is relatively suppressed and
the link without a column (21) is relatively stretchy.
[0034] This power transmission chain (1) is manufactured by holding
the necessary number of pins (14) and interpieces (15)
perpendicularly on a table and then, pressing the links (11) and
(12) one by one. They are pressed between the upper and lower edge
portions of the pin (14) and the interpiece (15) and between the
upper and lower edge portions of the pin fixing parts (12a), (22a)
and the interpiece fixing parts (13b), (23b); and the margin is
within the range of 0.005 mm to 0.1 mm.
[0035] When connecting the links (11) and (21) aligned in a chain
width direction, the links (11) and (21) are superimposed with each
other so that the front insertions parts (12), (22) of certain
links (11), (21) correspond to the back insertion parts (13), (23)
of other links (11), (21); the pin (14) is fixed to the front
insertion parts (12), (22) of the certain links (11), (21) and is
movably fitted in the back insertion parts (13), (23) of the other
links (11), (21); and the interpiece (15) is movably fitted in the
front insertion parts (12), (22) of the certain links (11), (21)
and is fixed to the back insertion parts (13), (23) of the other
links (11), (21). Then, this pin (14) and this interpiece (15) move
in a rolling and contacting manner relatively so as to enable
bending in a longitudinal direction (front and back direction) of
the links (11), (21). The locus of a contact position of the pin
(14) and the interpiece (15) based on the pin (14) is an involute
of a circle. In this embodiment, a contact surface (14a) of the pin
(14) is in an involute shape having a basic circle of a radius Rb
and the center M in a section, and a contact surface (15a) of the
interpiece (15) is flat (sectional shape is a line). Thereby, when
respective links (11) and (12) move from the linear part to the
circular part or moves from the circular part to the linear part of
the chain (1), in the front insertion parts (12) and (22), the
interpiece (15) moves such that the contact surface (15a) thereof
rolling-contacts the contact surface (14a) of the pin (14) with
respect to the fixed pin (14) in the interpiece movable parts (12b)
and (22b) (including a slight sliding contact), and in the back
insertion parts (13) and (23), the pin (14) moves in the pin
movable part (13a) such that the contact surface (14a) thereof
rolling-contacts the contact surface (15a) of the interpiece (15)
with respect to the fixed interpiece (15) (including a slight
sliding contact). In FIG. 3 and FIG. 4, the parts shown by the
reference marks A and B are lines (points in the section) where the
pin (14) and the interpiece (15) contact each other in the linear
part of the chain (1), and the distance between A and B is
considered as a pitch here.
[0036] The front insertion (22) and the back insertion part (23) of
the link without a column (21) are formed in the same shapes as the
front insertion part (12) and the back insertion part (13) of the
link with a column (11), so that it can be freely set on which
position the link with a column (11) and the link without a column
(21) are arranged.
[0037] According to the example shown in FIG. 1, all of the links
corresponding to the width direction of the chain (1) (one example)
fall into any of the link with a column (11) and the link without a
column (21). The illustration is herein omitted, however, in one
row, the link with a column (11) and the link without a column (21)
may be alternately arranged. In any case of that any one of the
link with a column (11) and the link without a column (21) is used
in one row and that the link with a column (11) and the link
without a column (21) are mixed in one row, it is not necessary
that the number of the link with a column (11) is equal to the
number of the link without a column (21) and the number of both is
decided depending on a balance between suppress of stretch and
relaxation of concentration of stresses.
[0038] FIG. 5 shows the other embodiment of the mixing pattern. In
FIG. 5, the links located at the most outside in the width
direction of each row are defined as the links (21) and the other
links are defined as the links (11). The links (21) arranged at the
opposite ends of the chain (1) receives a relatively large force.
Since these links (21) have no columns, the concentration of
stresses of the chain (1) is efficiently relaxed.
[0039] This power transmission chain (1) is used in a CVT shown in
FIG. 6, and in such a case, for example, the interpiece (the second
pin) (15) is set to be shorter than the pin (the first pin) (14),
and end faces of the pin (14) contact the conical sheave faces (2c)
and (2d) of the pulley (2) in a state where end faces of the
interpiece (15) do not contact respective conical sheave faces (2c)
and (2d) of the fixed sheave (2a) and the movable sheave (2b) of
the pulley (2), and power is transmitted by a frictional force
caused by this contact. Since the pin (14) and the interpiece (15)
move in a rolling and contacting manner as described above, the pin
(14) will seldom rotate with respect to the sheave faces (2c) and
(2d) of the pulley (2), whereby frictional loss is reduced and high
power transmission rate is secured.
[0040] Further, the above-described structure that the link with a
column (11) and the link without a column (21) are mixed also can
be applied to a chain that the lengths of the first pin and the
second pin are approximately the same and the both pins contact the
sheave faces. Further, this structure can be applied to a chain
that the both of the first pin and the second pin are movably
fitted in the front and back insertion parts and other various
types of the power transmission chains.
* * * * *